Reviewing for intro PDEs

I'm taking intro ODEs right now, and am taking intro PDEs next semester. I would like to know what i should review from calc III for this course.

I took calc III over the summer at a community college and didn't learn very much, if i'm being honest with myself. I think I am good as far as anything from calc I or II goes, and from this intro course in DEs as well. The title of this post could more suitably be "What from calc III is used in an intro PDEs course?" (and PDEs in the more general sense -- I plan on taking much more applied math in the coming three years).

So, what is used in partial differential equations form the typical calculus III course?